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H. F. HAGEN. CENTRIFUGAL FAN.

I APPLICATION FILED SEPT.26.19IB.

1 ,3 1 9,331 Patented Oct. 21, 1919.

l 2SHEETSSHEET 1. 1 'lg 1.

H. F. HAGEN. CENTRIFUGAL FAN} APPLICATION'FILED SEPT. 2a. 1918.

Patented Oct. 21, 1919.

2 SHEETSSHEET 2- Fig.

J nx/ember fl wn-(d. '7, 74'

M41377 ass UNITED STATES PATENT OFFICE.

HAROLD F. HAG-ED T, OF BOSTON, MASSACHUSETTS, ASSIGN'OR TO B. F. ST'U'RTEVANT COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

GENTRIF UGAL FAN.

Specification of Letters Patent.

Patented Oct. 21, 19 19.

Application filed September 26, 1918. Serial No. 255,743.

To all whom it may concern Be it known that I, HAROLD F. HAGEN, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Centrifugal Fans; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to centrifugal fans, and more particularly to that type of centrifugal fan which is adapted to be used for producing artificial draft in chimney stacks.

In order to secure increased draft with a chimney or stack it is a common practice to provide a fan at some convenient point between the furnace and the 'mouth of the stack which shall augment the draft of the stack in drawing ainthrough the furnace and in discharging the burnt gases through the stack into the atmosphere. Where such an induced draft involves high velocity of the burnt gases, a very considerable amount of solid material, such as cinders, ashes, etc., is carried along with the burnt gases and discharged from the mouth of the stack. In many localities the discharge of solid material with the gaseous products of combustion is objectionable, and screens or other forms of separating devices have been employed in the endeavor to separate the non-- gaseous from the gaseous material.

The object of the present invention is to construct a fan of the above type which shall not only operate at a high degree of efficiency in drawing the gaseous products ftrom the furnace and discharging them through the stack, but which at the same time will separate out the cinders or other non-gaseous material and divert such material from the stack into a suitable passage or receptacle.

With these and-other objects in view, as will hereinafter appear, the present invention consists in the devices and combinations of devices hereinafter described, and more particularly defined in the claims.

The preferred embodiment of the invention is illustrated in the drawings, in which Figure 1 is a side elevation of the fan, certain parts of the casing being broken away; Fig. 2 is an elevation, partly in section,

looking from the left in Fig. 1; Fig. 3 is a section on the line 33 of Fig. 2; Fig. 4 is a section on the line 4-4 of Fig. 2; and Fig. 5 is a perspective view of a portion of one of the blades.

The fan shown in the drawings comprises a rotary member or impeller and a stationary member or casing of the involute or snail-shaped type. The mixture of gaseous and non-gaseous material entering the opening or eye in the casing'coaxial with the rotary member is caught bythe blades of the latter and whirled around within the casing, the gaseous material being thrown oft the tips or outer edges of the blades and passing out through the tangentially arranged outlet or discharge opening while the nongaseous material is diverted toward the sides of the blades and discharged into separate cinder-receiving conduits on each side of the casing and of the gas conduit, and thence to any suitable or convenient point.

The rotary member of the fan comprises a spider 10 mounted upon the driving shaft 12 adapted to be rotated from any suitable source of power. Extending'from the spider are the straight radial arms 14: each carry-, ing a blade. The blade, instead of being formed of a single continuous plane or curved'surface with frusto-coni-cal rings or plates connecting their axial end edges, as heretofore has been the usual construction in fans of this type, is formed of a pair of plane surfaces offset from one another, the outer portion 16 being offset in the direction of rotation from the inner portion 18 'by means of two channel irons 20 extending from the medial line of the blade at a point somewhat nearer its inner than its outer edge, and in opposite directions to, and a short distance beyond, the axial edges or ends of the blade. The inner edge of the outer portion 16 projects inwardly beyond the channel iron 20so as to form a channel or conduit 22 which is deeper near the end shown in Fig. 2.

The frusto-conical rings which connect the i -f I end edges'of the blades instead of being edgesof the blade than at the middle, as H in its inner peripheral edge through which extend the projecting ends 28 of the channel irons 20, while the inner ring 24 has its outer peripheral edgeturned outwardly to form a narrow frusto-conical flange 30. The overlapping margins of the two rings are riveted together just within the flange. In order to diminish the air resistance the projecting ends of the channel irons are inclosed between the parallel, inclined flanges 32 and 34. The outer flange '32 is secured by rivets to the outer faces or bottoms of the channel irons, while the inner flange 34 is riveted to the narrow flange 30.

The inner portion of each blade is riveted to a radial arm 14, and both portions are attached to the rings 24: and 26 by means of rivets which pass through ears 36 extending from the ends of the blade portions at right angles thereto. By this method of securing together the blades, channel irons, and side rings, a strong, rigid structure is produced which will withstand without distortion or damage the strains incidental to the operation of the fan at relatively high speeds.

In operation the mixture of gaseous and non-gaseous material entering through the eye of the -fan is caught by the inner portion 18 of the rapidly rotating blade, and, on account of the centrifugal action developed, passes radially outward across the face of the blade. The non-gaseous material is trapped by the channel or conduit 22 between the inner and outer sections of the blade and is diverted laterally by the channel toward one side or the other and through the side rings and is finally discharged from be tween the flanges 32 and 34 on the side rings, while the gaseous material flows over the conduit 22, across the outer portion 16 of the blade, and is discharged from the outer edge thereof.

It has been found in practice that the separation of the non-gaseous from the gas eous material is made more effective and complete by the use of bafile plates 38 and 40 which are shown on the drawings as long, narrow, plane members, arranged in pairs on each side of the medial line of the fan blades, and located between the lanes of the blade portions 16 and 18. These baffle plates are offset different distances from the inner portion 18 of the blade, and from the inner edge of the outer portion 16, the outer plate 40 overlapping the edges of both inner plate 38 and outer blade portion 16. These baflle plates, it is believed, not only prevent the non-gaseous material, when struck by the inner portion 18 0f the blade, from rebounding sufliciently to pass over the inner edge ofthe outer portion 16, and serve to guide and direct such non-gaseous material into the conduit, but also permit the gaseous material to flow over the conduit 22 with less disturbance and eddying, thus increasing the The casing or stationary member of the fan comprises a middle or gasrcceiving portion, andat each side thereof an annular chamber for receiving the non-gaseous material. The middle or gas-receiving portion is substantially like the casings heretofore used with induced draft fans, and comprises the usual scroll or snail-shaped side plates 46 with the roundabout 48 and axial inlet pipe 50, and tangential outlet pipe 52, the opening opposite the inlet being closed by a flanged disk 54. The side plates i6, hoiw ever, instead of forming a continuous wall without openings, are provided with an an nular passage 56, through which extend the annular flanges 28 and 30 from the side rings of the rotary member.

The outer and inner portions of the casing are secured together in fixed relation by means of the walls 58 of the annular, dustreceiving chambers 60 which are attached to the side walls of the gas casing at each side of the annular passage 56 therethrmigh. These chambers 60 are formed of annular flat rings 62, connected to the inner and outer cylindrical rings 6i and 66 by means of the angle iron rings 68 to which they are riveted. Other angle iron rings 70, 7 O serve as a means for securing the cylindrical rings 64 and 66 to the side plates 46 on each side of the passage 56.

Each dust-receiving chamber 60 is connected at its lowest portion with the vertical section or passage 72 which merges beneath the base of the fan into a single passage 7- through which the non-gaseous material may be conducted to any suitable or convenient point.

The operation of the fan as a whole, so far as the gaseous material is concerned. is substantially the same as in fans heretoforev used for induced draft purposes. The products of combustion from the furnace enter through the inlet pipe 50 axially of the fan into the space within the inner edges of the rapidly revolving blades. As the gases are caught by the blades and whirled around rapidly they are forced radially outward by the centrifugal action developed and discharged from the outer edges of the blades into the casing at all points around the periphery of the rotary member, and in a direction approximating a tangent. The gases so discharged flow around inside the casing in the direction of rotation until they reach the outlet pipe through which they escape into the chimney or stack, and thence into the open air. 7

The non-gaseous material, such as the cinders carried along by the induced draft, flows with the gases of combustion into the interior of the fan, and are caught up with the gases by the inner edges of the blades. Being heavier than the gases, the non-gaseous material invariably lags behind the stream or mass of gas in front of each blade, and comes into contact with the advancing face of the blade or of one of the baffle plates, and is thence directed into the con-- duit22 either byactual contact with an inner surface of one of the baffle plates, or by the eddy currents caused thereby. Once caught in the conduit 22 the cinders or other non-gaseous material is carried to one side or the other of the fan into the dustreceiving chambers 60, and thence in the passages 72 and 74. y

The fan as above described not only operates at a high degree of efiiciency, so far as its gas moving function is concerned, but is exceedingly effective in removing the cinders or other non-gaseous material.

'VVhile the present invention has been shown and described as embodied in a fan for creating induced draft for furnaces, it is not necessarily limited thereto, but may be embodied in other constructions and used for separating other classes of non-gaseous from gaseous materials.

Having thus shown and described one form of the present invention, and explained its mode of operation, what is claimed is:

l. A centrifugal fan having, in combination, a driving shaft, a'plurality of blades constructed and arranged to receive a mix ture of gaseous and non-gaseous material and to discharge the gaseous material substantially tangentially and the nonaseous material laterally, means for supportlng the blades upon the shaft, and a casing having an axially arranged inlet opening for admitting the mixture of gaseous and nongaseous material to the blades, a peripherally arranged chamber for receiving the gaseous material and a laterally arranged chamber for receiving the non-gaseous material.

2. A centrifugal fan having, in combination, a driving shaft, a plurality of blades constructed and arranged to receive a mixture of gaseous and non-gaseous material and to discharge the gaseous material substantially tangentially and provided on their advancing faces with a conduit arranged obliquely to the axis of the shaft and extending to the lateral edge of the blade to receive and discharge laterally nongaseous material, means for supporting the blades upon the shaft, and means for admitting a mixture of gaseous and non-gaseous material to the blades and for receiving the non-gaseous material discharged from the conduits.

3. A centrifugal fan having, in combina tion, a driving shaft, a plurality of blades constructed and arranged to receive a mixture of gaseous and non-gaseous material and to discharge the gaseous material substantially tangentially and provided on their advancing faces with a conduit arranged obliquely tothe axis of the shaft and extending to the lateral edge of the blade to receive and discharge laterally nongaseous material, means for supporting the blades upon; the shaft, and a casing having an axially arranged inlet opening for admitting a mixture of gaseous and non-gase ous material to the blades, and having a side wall with an annular opening through which the non-gaseous material is delivered.

4. A centrifugal fan having, in combination, a driving shaft, a plurality of blades having inner and outer sections, the outer section being offset from-the inner section in the direction of rotation with their adjacent edges overlapping to form a conduit extending to the lateral edge of the blade and obliquely to the axis of the shaft, means for supportlng the blades upon the shaft, and a casing having provision for the ad mission axially to the blades of a mixture of gaseous and non-gaseous material and for the substantially tangential discharge of the gaseousmaterial and the lateral discharge of the non-gaseous material.

5. A centrifugal fan having, in combination, a driving shaft, a plurality of blades constructed and arranged to receive the mixture ofgaseous and non-gaseous material and provided witha conduit oblique to the axis of the shaft to receive the non-gaseous material and to discharge the same separately from the gaseous material, means for supporting the blades from the driving shaft, and a casing having provision for the admission axially to the blades of. a mixture of gaseous and non-gaseous material,

and for the discharge separately of the gasedischarge the same separately from the gaseous material, means for supporting the blades from the driving shaft, a casing having an axial intake opening for the admission of a mixture of gaseous and non-gaseous material to the blades, and a chamber to receive the gaseous material discharged from the blades and a separate chamber provided with an annular opening opposite the discharge ends of the conduits to receive the non-gaseous material.

7-. A centrifugal fan having, in combination, a driving shaft, a plurality of blades formed in two parallel planes with a conduit between to collect non-gaseous material, a baffle plate adjacent the conduit, means for supporting the blades from the driving shaft, and a casing having provision for the admission axially to the blades of a mixture of gaseous and non-gaseous material and for the discharge separately of the gaseous and non-gaseous material.

8. A centrifugal fan having, in combination, a driving shaft, a plurality of blades each provided with a conduit to collect nongaseous material, a baffle plate parallel with the blade and spaced therefrom, means for supporting the blades from the driving shaft, and a casing having provision for'the admission axially to the blades of a mixture of gaseous and non-gaseous material and for the discharge separately of the gaseous and non-gaseous material.

9. A centrifugal fan having, in combination, a driving shaft, a plurality of blades formed in two parallel planes with a conduit between open toward .the shaft to collect non-gaseous material, a plurality of baffle plates parallel with the blade planes and arranged in stepped formation with edges.

overlap-ping, means 1 for supporting the blades from the driving shaft, and a casing having'proylsion for the admission axially to the blades of a mixture of gaseous and non-gaseous material and for the discharge separately of the gaseous and non-gaseous material.

10. A centrifugal fan having; in combination, a driving shaft, a plurality of blades mounted upon the shaft and adapted to receive a mixture of gaseous and non-gaseous material axially and to deliver the gaseous material substantially tangentially and the non-gaseous material laterally, and a fan casing comprising a scroll-shaped outer wall and side walls to form a gas conducting passage to receive the gaseous material delivered tangentially, and a circular chamber at the side of the gas conducting chambei to receive the non-gaseous material delivered laterally.

11. A centrifugal fan having, in combination, a driving shaft, a plurality of blades mounted upon the shaft and adapted to re ceive a mixture of gaseous and non-gaseous material provided with a conduit oblique tothe axis of the shaft to receive the nongaseous material and to discharge the same laterally, rings connecting the ends of the blades, the conduits extending through and projecting beyond the rings, flanges inclosing the projecting conduits, and a fan casing comprising an outer wall and side walls to form a gas conducting passage to receive the gaseous material delivered tangentially, and a circular chamber at the side of the gas conducting chamber to receive the non-gaseous material delivered laterally, the wall between the two chambers being being pro vided with a continuous, circular opening through which the flanges project.

12. A centrifugal fan having, in combination, a driving shaft, a plurality of blades mounted upon the driving shaft and adapted to receive a mixture of gaseous and nongaseous material axially and to discharge the gaseous material substantially tangentially and the m n-gaseous material laterally, the blades comprising an inner and an outer portion, overlapping at their adjacent edges and connected by a transverse plate to form a pair of conduits extending from the medial line of the blades obliquely to the axis, rings connecting the blades at each end, the rings having outturned flanges spaced apart to form a passage with which the conduits communicate, a casing having an axial inlet and a middle ga s-discharge chamber, and an annular chamber on each side of the gas chamber to receive the nongaseous material, and connected by a narrow, annular passage with said gas chamber, through which passage the flanges of the rings project.

HAROLD F. HAGEN. 

